Electerochemical study of sulfonated poly ether ether ketone nanocomposite membrane for direct methanol fuel cell application

Abstract

High methanol permeability and expensive price of current commercial Nafion® membrane for direct methanol fuel cell (DMFC) have encouraged researchers to modify proton exchange membrane (PEM). Sulfonted poly ether ether ketone (SPEEK) is a polymer which attracted a lot of attention recently. This study aimed to test the DMFC performance of nanocomposite SPEEK membrane filled with Cloisite 15A® clay by introducing 2,4,6 triaminopyrimidine (TAP) as a compatibilizer as electrolyte membrane at room temperature to 80oC and compare with Nafion 117. SPEEK polymer was made at 60oC in order to obtain the degree of sulfonation of 60%. According to the results, the SPEEK nanocomposite with the following composition SP60/CL2.5/TAP5.0 showed higher proton conductivity and methanol permeability than of Nafion 117 at various temperatures because of the presence of CL and TAP addition.Furthemore the highest overall performance( membrane selectivity) was allocated to the SP60/CL2.5/TAP5.0 at 60oC while the lowest one was for Nafion 117 at 80oC. In addition DMFC performance results showed the OCV for the nanocomposite membrane increase when the temperature increase. In addition voltage and power density increase with temperature incerement due to catalyst high activity on electrode surface,and higher proton conductivity , clearly the maximum power density at 60oC was 54.93 (mWcm-2).